Effect of maternal diet and body composition on lactational performance.

Milk production, dietary intake, and body composition of 45 lactating women were monitored for 4 months postpartum to examine the interrelationships of these maternal variables. A 3-day dietary record, 24-h test-weighing for determination of milk production, 24-h milk collection, anthropometric measurements, and water displacement for estimation of body fat were performed monthly. The overall mean (SD) energy intake was 2186 (463) kcal/day. Milk production (g/day) averaged 751 (130), 725 (131), 723 (114), and 740 (128) during the 4 sequential months. Weight postpartum was 64.6 (9.1) kg and was 59.3 (10.5) kg at 4 months. Body fat determined by water displacement averaged 28 (7)% at 1 month and 26 (8)% at 4 months. Estimations of body fat from skinfold thickness ranged from 28 (5)% postpartum to 27 (5)% at 4 months. Energy balance calculations based on the energy available from the diet plus the energy derived from tissue mobilization, minus the caloric equivalent of the milk, indicated sufficient energy available for maintenance and activity needs. Thus, it appears that successful lactation is compatible with gradual weight reduction and attainable with energy intakes less than current recommendations.